The subject matter disclosed herein relates generally to gamma ray detectors, and more particularly, to systems and methods for communicating signals in gamma ray detectors.
Gamma ray detectors may be used in different applications, such as in Positron Emission Tomography (PET) systems. PET systems perform nuclear medicine imaging that generates a three-dimensional image or picture of functional processes within a body. For example, a PET system generates images that represent the distribution of positron-emitting nuclides within the body of a patient. When a positron interacts with an electron by annihilation, the entire mass of the positron-electron pair is converted into two 511 keV photons. The photons are emitted in opposite directions along a line of response. The annihilation photons are detected by detectors that are placed along the line of response on a detector ring. When these photons arrive and are detected at the detector elements at the same time, this is referred to as coincidence. An image is then generated based on the acquired image data that includes the annihilation photon detection information.
In silicon photomultiplier based PET detectors, in order to cover a large area for detection of gamma rays, a large number of small area silicon photomultipliers (e.g., 3×3 mm2 or 4×4 mm2 photomultiplier devices) are used. The large number of these photomultipliers increases the complexity of the devices, as well as the number of readout channels.
In order to reduce the number of channels, as well as the complexity of handling many small individual pixels (e.g., a one anode device or a one anode per pixel device), monolithic devices (e.g., a device with many pixels) having larger areas may be used, such as for PET-Magnetic Resonance (PET-MR) detectors. However, these monolithic devices have anode readout traces that cause cross-talk through inductive and capacitive electric coupling. Additionally, larger pixels exhibit a larger transit time spread due to size, as well as the location of the various signal summing points.
Thus, known architectures for signal communication in gamma ray detectors, particularly using solid state photomultipliers may not work satisfactorily and have complex controls.